1. Field of the Invention
The present invention relates to a shift lock device operable between its locking and unlocking states for inhibiting and permitting a shifting movement of a shift lever provided in a vehicle such as an automobile.
2. Discussion of Related Art
In the field of automotive vehicles provided with an automatic transmission, there is known a shift lock device having a locking state for locking a shift lever in its parking position. In this locking state, the shift lever is prevented from being operated from the parking position to any other operating position unless a brake pedal is in its operated position. An example of this vehicular shift lock device is disclosed in JP-8-216722A.
The shift lock device disclosed in the above-identified publication is arranged to be placed in its unlocking position when a detent knob provided on the shift lever is operated. This shift lock device includes: a lock plate movable by a depressing operation of the detent knob; a cam member which has a cam surface and which is movable when the cam surface is pushed by the lock plate; a stopper member biased by a spring toward its stopping position for preventing a movement of the lock plate; and a solenoid-operated device operable to connect the stopper member and the cam member to each other. When the detent knob is depressed, the lock plate is linearly movable downwards while pushing the cam surface of the cam member, whereby the cam member is linearly laterally movable. When a solenoid of the solenoid device is in its energized state, the stopper member is laterally moved with the cam member, so that the lock plate can be moved downwards to its unlocking position. When the solenoid is in its de-energized state, on the other hand, only the cam member is laterally moved while the stopper member remains in its stopping position in which the downward movement of the lock plate is prevented by the stopper member, so that the lock plate is held in its locking position.
There is also known a gate-type shift lever which is not provided with a detent knob and which is capable of functioning as the detent knob, so that this gate-type shift lever has an improved ease of operation or use. Namely, this shift lever functions as a manually operable unlocking member to place a shift lock device in its unlocking position when the shift lever is operated (pivoted) laterally of the vehicle. To place the shift lock device in the unlocking position, the shift lever is operated laterally from its parking position. The shift lock device used with the gate-type shift lever includes a stopper member which is movable between its stopping position for preventing a lateral movement of the shift lever from its parking position, and its non-stopping for permitting the lateral movement. In this shift lock device, the stopper member, cam member, etc. are arranged to be linearly movable.
For easy operation of the manually operable member operated to place the shift lock device to its unlocking position, the operating stroke of the manually operable member is desirably short. In the shift lock device wherein the lock plate, cam member and stopper member are all linearly moved, it is difficult to sufficiently amplify the operating stroke of the manually operable member into the linear movements, although some degree of amplification of the operating stoke is possible by determining an angle of inclination of the cam surface of the cam member so as to amplify the operating stroke. Accordingly, the required operating stroke of the manually operable member tends to be large. This is contrary to the desirability of reducing the required operating stroke of the manually operable member.